Yanma in depth
Yanma means yanma
The name is not a pun: it is the word itself. In Japanese, 蜻蜓 (yanma) refers to large dragonflies in the family Aeshnidae, the ones Spanish calls caballitos del diablo or emperor dragonflies depending on the species. The Japanese name, ヤンヤンマ (Yanyanma), adds やんや (yanya) at the front, an approving interjection similar to “bravo”. The extra syllable was trimmed in translation, leaving Yanma on its own, a form shared by English, French, German, Italian, Portuguese and Spanish. Korean went in a different direction with 왕자리 (Wangjari).
The specific model points to an anisopteran with dark bands on its wings, but its size does not match any living dragonfly. That is where the other reference comes in: Meganeura, the genus of Carboniferous insects with a wingspan of almost seventy centimetres that is commonly translated as “griffinflies”. That prehistoric reading explains the odd evolution method better than anything else.
Ancient Power as the key
Making evolution depend on Ancient Power is not a programmer’s whim. It is a Rock-type move — the type that suits it worst, incidentally — and its name in every language points to the distant past. A modern insect remembering an ancient blow becomes the giant version of itself. The mechanic debuted in the fourth generation, two generations after Yanma’s debut, so during Gold, Silver and Crystal it was a species with no evolution and no apparent reason to have 390 total stats.
In practice, the requirement almost takes care of itself, because the move enters its learnset at level 33 and level 34 triggers evolution. Problems appear when someone wants to keep it unevolved and fills all four move slots with something else.
What changes and what does not
Yanmega gains bulk almost everywhere: 86 HP, 86 Defense and 116 Special Attack compared with this form’s 65, 45 and 75. Special Defense rises only slightly, from 45 to 56, and Speed does not rise at all. Both forms have exactly 95, which is unusual for an evolutionary line and leaves Yanma with one stat in which it loses nothing by not evolving. As an argument for staying unevolved, it is weak, because everything else adds up to a 125-point difference in the total.
Against Masquerain, the other mid-sized special Bug/Flying Pokémon, Yanma gives up Special Attack and staying power in exchange for fifteen points of Speed and an Ability that keeps working turn after turn. It is the difference between hitting hard from the start and needing the battle to last.
Its appearance history has been uneven. It debuted on Johto’s Route 35 in Gold, Silver and Crystal, turned up in Sinnoh’s Great Marsh, was left out of Sword and Shield and returned in the DLC for Scarlet and Violet. For a creature whose entire pitch is mobility, it is amusing how difficult it is for it to show up.